100 Messrs. Kanthack, Durham, and Blandford. 



number of bands concerned is about 96 per atmosphere of air, or about 

 62 over the range actually used. It is wise always to include a match 

 with pressures about midway between the extremes. If the results 

 harmonise, an error of a single band is excluded, and it is hardly 

 possible to make a mistake of two bands. 



As regards accuracy, independent final results usually agree to one- 

 thousandth part. 



" On Nagana, or Tsetse Fly Disease. (Report, made to the Tsetse 

 Fly Committee' of the Koyal Society, of Observations and 

 Experiments carried out from November, 1896, to August, 

 1898.)" By A. A. KANTHACK, H. E. DURHAM, and W. F. H. 

 BLANDFOED. Eeceived October 27, 1898. 



At the request of the Colonial Office, the Eoyal Society of London 

 appointed a Committee to co-operate with Surgeon-Major Bruce in his 

 research upon Nagana or the Tsetse Fly disease. This Committee 

 entrusted us with the actual experimental work. The object was to 

 study Nagana systematically in ordinary laboratory animals, to investi- 

 gate the life-history of the hsematozoon discovered by Bruce, and, if 

 possible, to discover methods of prevention, cure, or immunisation. 



The material for our observations was obtained in the first instance 

 from the blood of a dog infected by the disease on the voyage from 

 Africa, and brought to England in November, 1896, by Dr. Waghorn. 



The investigation was begun at once at the pathological laboratory 

 of St. Bartholomew's Hospital, but in February, 1897, was transferred 

 to the pathological laboratory of the University of Cambridge. 



The Hcematozoon of nagana has already been described by Bruce, and 

 is closely allied to the Trypanosonw of Surra. We have had no oppor- 

 tunity of studying the latter disease, the relation of which to nagana is 

 referred to later. The parasite discovered and described by Rouget* 

 in a horse in Algeria is also similar. In English sewer rats (Mus decu- 

 manus) a Trypanosomci (T. sanguinis) is occasionally found, but this is 

 quite distinct from the hsematozoon of nagana, both in its morpho- 

 logical appearance and in its pathogenic effects (vide infra). 



I. Susceptibility. 



Oats, dogs, mice, rabbits, rats, both sewer rats (Mus decumanus) and 

 white and piebald rats (Mus rattus), are highly susceptible, and in these 

 animals the disease has proved fatal in every case of infection which 

 has been allowed to run to a close. 



* ' Annales de 1'Institut Pasteur,' 1896, p. 716. 



